The president’s call prompted a year long review ending this December, but Senators are attempting to push through change quicker.

Senator Joe Lieberman is trying to overturn the current law: “We’re going for full repeal because that really is the solution we need to this problem. We’re going to fight for as much support as we can get.

But the US defence secretary Robert Gates supports Mr Obama’s position but does not want to introduce changes to the law until the end of the review.

His spokesman said: “Right now, we’re not in a position to offer any advice to Congress on a legislative remedy to ‘don’t ask, don’t tell’ if they wanted to pursue one. We just don’t know enough about the impacts.

“The secretary wants to take the next nine, ten months and focus on figuring out the implications of a change in the law for our forces, for their families, for readiness, for recruiting, for retention, for all of the potential consequences of the change in the law.”

General James Conway told a Senate Armed Services Committee hearing that he believed that the current policy works: ““I think the current policy works. At this point. . . my best military advice to this committee, to the [defence] secretary, to the president would be to keep the law such as it is.”

He added that repealing the ban should not be a question of fairness. Instead, he said, the question was whether it would “enhance the war-fighting of the United States Marine Corps.”

Last week, Mr Lieberman said: “I will be proud to be a sponsor of the important effort to enable patriotic gay Americans to defend our national security and our founding values of freedom and opportunity.

“I have opposed the current policy of preventing gay Americans from openly serving in the military since its enactment in 1993.”